The present invention relates to a hydraulic valve arrangement with control/regulating function, a backflow valve for the hydraulic valve arrangement, a hydraulic drive system with at least one hydraulic valve arrangement, and a mobile machine with the hydraulic drive system.
Seat valves in cartridge construction are available on the market today in a variety of designs. Various manufacturers offer a wide product range of seat valves from very small ones up to very large nominal sizes. It has turned out that seat valves of small nominal sizes frequently are used in pilot control systems of hydraulic circuits. This applies both for mobile and for stationary hydraulic systems. Seat valves for high oil volume flows chiefly are used in stationary hydraulic systems.
The available seat valves in cartridge construction mostly are controlled by external signals (pressure signals, electrical signals) and need to be included in the system via an external control unit. This means that cartridge valves existing today do not have the functions mentioned below, which are necessary for the use in a mobile machine. When the existing cartridge valves are to be used in a hydraulic control system of a mobile machine, it is found in a multitude of invention applications that an electronic or electric control unit always takes over the algorithms for performing the control/regulating functions of the hydraulic drives and correspondingly controls the valves.
As an example for such hydraulic control system for a machine, the publication DE 11 2004 001 916 T5 can be mentioned.
In general, hydraulic valves are provided to realize functions for ensuring the proper operation of the hydraulic consumers within the hydraulic control system of a mobile machine (excavator, wheel loader, crane, etc.). The functions of the hydraulic valves differ by the types of valve (summation valves, inflow valves and backflow valves).
Within a hydraulic control system in particular of a mobile machine, the novel hydraulic valves have the task of realizing the control of oil volume flows in dependence on specific states within the hydraulic system and of external control signals.
This connection should be realized as a function of the backflow valve within the consumer interconnection. The backflow valve should open or close in dependence on the consumer inflow pressure, in order to throttle the consumer return volume flow such that a corresponding consumer inflow pressure is maintained. Thus, the backflow valve should be adjusted directly by the hydraulic consumer inflow pressure.